I think part of this boils down to many theists believe it's better to believe in some god than no god. While they may be driving around with dirty Christian sayings in their bus, at least they're not propagating the message of the filthy atheists that there is no god. Christians and Muslims may generally hate each other, but I don't think that hate scratches the surface for what they harbor against us atheists.
Even if the open windows of science at first make us shiver after the cozy indoor warmth of traditional humanizing myths, in the end the fresh air brings vigor, and the great spaces have a splendor of their own - Bertrand Russell
